1. Field of the Invention
This invention relates to a sensor of pneumatic tire, and more specifically to a condition sensor of pneumatic tire for securely attaching to the rim of the tire.
2. Description of the Related Art
It is well known in the prior art that a variety of devices can be used to inspect the pressure of the pneumatic tire of vehicle, such as U.S. Pat. No. 4,048,614 entitled xe2x80x9cLow Tire Pressure Warning Devicexe2x80x9d, issued to Shumway on Sep. 13, 1997, which discloses a tire warning device for pneumatic tires of a vehicle. The tire warning device is mounted to the wheel rim and has an actuatable radio transmitter, a power source, a switch, and a diaphragm means. The radio transmitter can be actuated to warn the driver when the pressure of the tire is below a predetermined low pressure. The warning device described above only warns the driver of the low pressure of the tire, and is constructed with complex structure which is not adapted to the modern vehicle.
U.S. Pat. No. 5,844,131 entitled xe2x80x9cTire Pressure Sensor Apparatus For A Pneumatic Tire Of A Vehiclexe2x80x9d, issued to Gabelmann et al. on Dec. 1, 1998, discloses a pressure sensor device comprising a housing having at least two base elements for resting on a rim bed of a tire rim and for adjustably supporting the housing in a mounted state. As mentioned above, since the rim bed is cylindrical or barrel shape, the housing is supported to the rim bed by the two base elements when it is mounted on the rim bed. However, due to the vehicle jolting along, such a two-point contact is often loosened and the housing cannot be securely mounted on the rim bed. Besides, the sensor device is mounted on the rim of the tire by the two base elements as well as a tire valve and a hollow screw attached thereto, but this arrangement needs cooperating with three contact points, and thus it is difficult to install and to mount the sensor device on a variety of rims. Also, the antenna member is necessary for the pressure sensor, and it is extended from the housing. When the tire is repaired, the antenna member will be often damaged by the repairing tools, and then the pressure sensor will be replaced.
Moreover, U.S. Pat. No. 6,055,855 entitled xe2x80x9cTire Pressure Sensor Wheel Attachment Apparatusxe2x80x9d, issued to Straub on May 2, 2000, discloses an apparatus for mounting a pressure sensor on a rim of a vehicle wheel, in which the apparatus comprises a pressure sensor and a threaded fastener, and the pressure sensor can be mounted on the rim of the wheel by the threaded fastener and a tire valve stem. The mounting effect only from the tire valve stem cannot provide sufficient support to meet the requirement of the apparatus. Furthermore, this apparatus includes a spherical surface to be adjustably attached on the rim, but this spherical surface will substantially decrease the stability of the apparatus.
Therefore, the tire pressure sensor as described hereinbefore cannot be securely mounted on the rim of the wheel, and a need exists therefor to provide a suitable pressure device to be securely attached to the rim of the tire of vehicle so as to inspect the tire condition at any time.
It is the primary object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor can be securely mounted to the rim of the tire and interact with receiver means outside of the tire.
It is another object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor is mounted to the rim of the tire and is constructed as a relatively compact structure such that the condition sensor will not be damaged by the tire repairing tools.
It is a further object of the present invention to provide a condition sensor of a pneumatic tire to inspect the condition of the tire, in which the condition sensor has an adjustable structure so as to facilitate the securely attachment of the condition sensor on the rim of the tire.
In order to achieve the above objects, the condition sensor of pneumatic tire according to the present invention is configured to be attached on a pneumatic tire of a vehicle, and the pneumatic tire has a rim with a rim bed. The condition sensor comprises a sensor circuit to detect the condition of the tire, a power source to supply the sensor circuit with electric power; and a housing having a cover portion and a base portion, in which the base portion is used to receive the sensor circuit and the power source. The cover portion is provided with an arc-concave surface having a convexity, in which the arc-concave surface is in arc-line contact with the rim bed and the convexity can be used to adjust the relationship position between the housing and the rim bed.
According to one aspect of the present invention, the condition sensor of pneumatic tire further comprises a valve stem cavity having a hole and a tire valve stem, the rim of the tire having a tire valve hole, and the condition sensor being adjustably mounted on the tire valve hole by means of the valve stem cavity.
According to another embodiment of the present invention, the condition sensor of pneumatic tire is configured to be attached on a pneumatic tire of a vehicle, and the pneumatic tire having a rim with a rim bed. The condition sensor comprises a sensor circuit to dectect the condition of the tire, a power source to supply the sensor circuit with electric power, a housing to receive the sensor circuit and be mounted on the rim bed, the housing has a cover portion and a base portion, in which the base portion is used to receive the sensor circuit and the power source and comprise two grooves, and the cover portion is provided with a valve stem cavity and a tire valve stem, and the rim having a tire valve hole; and two one-way sliders to cooperate with the two grooves such that the one-way slider can slide inside the groove in one way and the condition sensor can be securely mounted on the tire valve hole by means of the tire valve stem through the valve stem cavity and the two one-way sliders.
According to another aspect of the present invention, the condition sensor of pneumatic tire further comprises an antenna to transmit radio signal and interact with receiver means outside of the tire, the antenna is arranged alone the surface of the base portion to reduce the probability of the antenna being damaged.
According to the present invention, since the condition sensor of pneumatic tire is provided with an arc-concave surface to fit with the rim bed of the pneumatic tire, the condition sensor can be securely attached to the rim of the tire. Also, the condition sensor has an antenna member without any protruding structure, and thus the antenna member of the condition sensor will not be damaged during repairing of the tire.